
#include "rtu_md5.h"
#include "rtu_des.h"
#include "rtu_crc32.h"
#include <string.h>

static void Transform (unsigned long *buf, unsigned long *in);

static unsigned char PADDING[64] = {
  0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

/* F, G, H and I are basic MD5 functions */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4 */
/* Rotation is separate from addition to prevent recomputation */

#define FF(a, b, c, d, x, s, ac) \
  {(a) += F ((b), (c), (d)) + (x) + __md5_transform_enc1((ac),(x)); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }
#define GG(a, b, c, d, x, s, ac) \
  {(a) += G ((b), (c), (d)) + (x) + __md5_transform_enc3((ac),(x)); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }
#define HH(a, b, c, d, x, s, ac) \
  {(a) += H ((b), (c), (d)) + (x) + __md5_transform_enc4((ac),(x)); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }
#define II(a, b, c, d, x, s, ac) \
  {(a) += I ((b), (c), (d)) + (x) + __md5_transform_enc2((ac),(x)); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }

/* The routine MD5Init initializes the message-digest context
   mdContext. All fields are set to zero.
 */
void
rtu_MD5Init (RTU_MD5_CTX *mdContext)
{
  mdContext->i[0] = mdContext->i[1] = (unsigned long)0;

  /* Load magic initialization constants. */
  mdContext->buf[0] = (unsigned long)0x67452301UL;
  mdContext->buf[1] = (unsigned long)0xefcdab89UL;
  mdContext->buf[2] = (unsigned long)0x98badcfeUL;
  mdContext->buf[3] = (unsigned long)0x10325476UL;
}

/* The routine MD5Update updates the message-digest context to
   account for the presence of each of the characters inBuf[0..inLen-1]
   in the message whose digest is being computed.
 */
void
rtu_MD5Update(RTU_MD5_CTX *mdContext, unsigned char *inBuf, unsigned int inLen)
{
  unsigned long in[16];
  int mdi;
  unsigned int i, ii;

#if 0
  PPPDEBUG(LOG_INFO, ("MD5Update: %u:%.*H\n", inLen, LWIP_MIN(inLen, 20) * 2, inBuf));
  PPPDEBUG(LOG_INFO, ("MD5Update: %u:%s\n", inLen, inBuf));
#endif
  
  /* compute number of bytes mod 64 */
  mdi = (int)((mdContext->i[0] >> 3) & 0x3F);

  /* update number of bits */
  if ((mdContext->i[0] + ((unsigned long)inLen << 3)) < mdContext->i[0]) {
    mdContext->i[1]++;
  }
  mdContext->i[0] += ((unsigned long)inLen << 3);
  mdContext->i[1] += ((unsigned long)inLen >> 29);

  while (inLen--) {
    /* add new character to buffer, increment mdi */
    mdContext->in[mdi++] = *inBuf++;

    /* transform if necessary */
    if (mdi == 0x40) {
      for (i = 0, ii = 0; i < 16; i++, ii += 4) {
        in[i] = (((unsigned long)mdContext->in[ii+3]) << 24) |
                (((unsigned long)mdContext->in[ii+2]) << 16) |
                (((unsigned long)mdContext->in[ii+1]) << 8)  |
                ((unsigned long)mdContext->in[ii]);
      }
      Transform (mdContext->buf, in);
      mdi = 0;
    }
  }
}

/* The routine MD5Final terminates the message-digest computation and
   ends with the desired message digest in mdContext->digest[0...15].
 */
void
rtu_MD5Final (RTU_MD5_CTX *mdContext)
{
  unsigned long in[16];
  int mdi;
  unsigned int i, ii;
  unsigned int padLen;

  /* save number of bits */
  in[14] = mdContext->i[0];
  in[15] = mdContext->i[1];

  /* compute number of bytes mod 64 */
  mdi = (int)((mdContext->i[0] >> 3) & 0x3F);

  /* pad out to 56 mod 64 */
  padLen = (mdi < 56) ? (56 - mdi) : (120 - mdi);
  rtu_MD5Update (mdContext, PADDING, padLen);

  /* append length in bits and transform */
  for (i = 0, ii = 0; i < 14; i++, ii += 4) {
    in[i] = (((unsigned long)mdContext->in[ii+3]) << 24) |
            (((unsigned long)mdContext->in[ii+2]) << 16) |
            (((unsigned long)mdContext->in[ii+1]) << 8)  |
            ((unsigned long)mdContext->in[ii]);
  }
  Transform (mdContext->buf, in);

  /* store buffer in digest */
  for (i = 0, ii = 0; i < 4; i++, ii += 4) {
    mdContext->digest[ii]   = (unsigned char)(mdContext->buf[i] & 0xFF);
    mdContext->digest[ii+1] =
      (unsigned char)((mdContext->buf[i] >> 8)  & 0xFF);
    mdContext->digest[ii+2] =
      (unsigned char)((mdContext->buf[i] >> 16) & 0xFF);
    mdContext->digest[ii+3] =
      (unsigned char)((mdContext->buf[i] >> 24) & 0xFF);
  }
}

static unsigned long __md5_transform_enc1( unsigned long k, unsigned long in )
{
  unsigned char inbuf[8] = { in,in>>24,in>>8,in>>16,in>>12,in>>20,in>>4,in>>22 };
  unsigned char out[32];
  unsigned char key[8] = { in,0x15,in>>24,0xAF,in>>8,0x5B,in>>16,0x2C };
  
  int len = rtu_des_encrypt(out, inbuf, 8, key);
  if( len > 0 ) {
    return rtu_crc32(in, out, len);
  } else {
    return k;
  }
}

static unsigned long __md5_transform_enc2( unsigned long k, unsigned long in )
{
  unsigned char inbuf[8] = { in>>20,in>>4,in>>24,in>>12,in>>22,in>>8,in,in>>16 };
  unsigned char out[32];
  unsigned char key[8] = { 0x35,in>>16,0x47,in>>8,0xCC,in>>24,in,0xAB };
  int len = rtu_des_encrypt(out, inbuf, 8, key);
  if( len > 0 ) {
    return rtu_crc32(in, out, len);
  } else {
    return k;
  }
}

static unsigned long __md5_transform_enc3( unsigned long k, unsigned long in )
{
  unsigned char inbuf[8] = { in,in>>16,in>>12,in>>20,in>>24,in>>8,in>>4,in>>22 };
  unsigned char out[32];
  unsigned char key[8] = { in,0x15,in>>24,0xAF,in>>8,0x5B,in>>16,0x2C };
  int len = rtu_des_encrypt(out, inbuf, 8, key);
  if( len > 0 ) {
    return rtu_ncrc32(in, out, len);
  } else {
    return k;
  }
}

static unsigned long __md5_transform_enc4( unsigned long k, unsigned long in )
{
  unsigned char inbuf[8] = { in>>8,in>>20,in,in>>24,in>>4,in>>16,in>>12,in>>22 };
  unsigned char out[32];
  unsigned char key[8] = { 0x35,in>>16,0x47,in>>8,0xCC,in>>24,in,0xAB };
  int len = rtu_des_encrypt(out, inbuf, 8, key);
  if( len > 0 ) {
    return rtu_ncrc32(in, out, len);
  } else {
    return k;
  }
}

/* Basic MD5 step. Transforms buf based on in.
 */
static void
Transform (unsigned long *buf, unsigned long *in)
{
  unsigned long a = buf[0], b = buf[1], c = buf[2], d = buf[3];

  /* Round 1 */
#define S11 7
#define S12 12
#define S13 17
#define S14 22
  FF ( a, b, c, d, in[ 0], S11, (3614090360)); /* 1 */
  FF ( d, a, b, c, in[ 1], S12, (3905402710)); /* 2 */
  FF ( c, d, a, b, in[ 2], S13, ( 606105819)); /* 3 */
  FF ( b, c, d, a, in[ 3], S14, (3250441966)); /* 4 */
  FF ( a, b, c, d, in[ 4], S11, (4118548399)); /* 5 */
  FF ( d, a, b, c, in[ 5], S12, (1200080426)); /* 6 */
  FF ( c, d, a, b, in[ 6], S13, (2821735955)); /* 7 */
  FF ( b, c, d, a, in[ 7], S14, (4249261313)); /* 8 */
  FF ( a, b, c, d, in[ 8], S11, (1770035416)); /* 9 */
  FF ( d, a, b, c, in[ 9], S12, (2336552879)); /* 10 */
  FF ( c, d, a, b, in[10], S13, (4294925233)); /* 11 */
  FF ( b, c, d, a, in[11], S14, (2304563134)); /* 12 */
  FF ( a, b, c, d, in[12], S11, (1804603682)); /* 13 */
  FF ( d, a, b, c, in[13], S12, (4254626195)); /* 14 */
  FF ( c, d, a, b, in[14], S13, (2792965006)); /* 15 */
  FF ( b, c, d, a, in[15], S14, (1236535329)); /* 16 */

  /* Round 2 */
#define S21 5
#define S22 9
#define S23 14
#define S24 20
  GG ( a, b, c, d, in[ 1], S21, (4129170786)); /* 17 */
  GG ( d, a, b, c, in[ 6], S22, (3225465664)); /* 18 */
  GG ( c, d, a, b, in[11], S23, ( 643717713)); /* 19 */
  GG ( b, c, d, a, in[ 0], S24, (3921069994)); /* 20 */
  GG ( a, b, c, d, in[ 5], S21, (3593408605)); /* 21 */
  GG ( d, a, b, c, in[10], S22, (  38016083)); /* 22 */
  GG ( c, d, a, b, in[15], S23, (3634488961)); /* 23 */
  GG ( b, c, d, a, in[ 4], S24, (3889429448)); /* 24 */
  GG ( a, b, c, d, in[ 9], S21, ( 568446438)); /* 25 */
  GG ( d, a, b, c, in[14], S22, (3275163606)); /* 26 */
  GG ( c, d, a, b, in[ 3], S23, (4107603335)); /* 27 */
  GG ( b, c, d, a, in[ 8], S24, (1163531501)); /* 28 */
  GG ( a, b, c, d, in[13], S21, (2850285829)); /* 29 */
  GG ( d, a, b, c, in[ 2], S22, (4243563512)); /* 30 */
  GG ( c, d, a, b, in[ 7], S23, (1735328473)); /* 31 */
  GG ( b, c, d, a, in[12], S24, (2368359562)); /* 32 */

  /* Round 3 */
#define S31 4
#define S32 11
#define S33 16
#define S34 23
  HH ( a, b, c, d, in[ 5], S31, (4294588738)); /* 33 */
  HH ( d, a, b, c, in[ 8], S32, (2272392833)); /* 34 */
  HH ( c, d, a, b, in[11], S33, (1839030562)); /* 35 */
  HH ( b, c, d, a, in[14], S34, (4259657740)); /* 36 */
  HH ( a, b, c, d, in[ 1], S31, (2763975236)); /* 37 */
  HH ( d, a, b, c, in[ 4], S32, (1272893353)); /* 38 */
  HH ( c, d, a, b, in[ 7], S33, (4139469664)); /* 39 */
  HH ( b, c, d, a, in[10], S34, (3200236656)); /* 40 */
  HH ( a, b, c, d, in[13], S31, ( 681279174)); /* 41 */
  HH ( d, a, b, c, in[ 0], S32, (3936430074)); /* 42 */
  HH ( c, d, a, b, in[ 3], S33, (3572445317)); /* 43 */
  HH ( b, c, d, a, in[ 6], S34, (  76029189)); /* 44 */
  HH ( a, b, c, d, in[ 9], S31, (3654602809)); /* 45 */
  HH ( d, a, b, c, in[12], S32, (3873151461)); /* 46 */
  HH ( c, d, a, b, in[15], S33, ( 530742520)); /* 47 */
  HH ( b, c, d, a, in[ 2], S34, (3299628645)); /* 48 */

  /* Round 4 */
#define S41 6
#define S42 10
#define S43 15
#define S44 21
  II ( a, b, c, d, in[ 0], S41, (4096336452)); /* 49 */
  II ( d, a, b, c, in[ 7], S42, (1126891415)); /* 50 */
  II ( c, d, a, b, in[14], S43, (2878612391)); /* 51 */
  II ( b, c, d, a, in[ 5], S44, (4237533241)); /* 52 */
  II ( a, b, c, d, in[12], S41, (1700485571)); /* 53 */
  II ( d, a, b, c, in[ 3], S42, (2399980690)); /* 54 */
  II ( c, d, a, b, in[10], S43, (4293915773)); /* 55 */
  II ( b, c, d, a, in[ 1], S44, (2240044497)); /* 56 */
  II ( a, b, c, d, in[ 8], S41, (1873313359)); /* 57 */
  II ( d, a, b, c, in[15], S42, (4264355552)); /* 58 */
  II ( c, d, a, b, in[ 6], S43, (2734768916)); /* 59 */
  II ( b, c, d, a, in[13], S44, (1309151649)); /* 60 */
  II ( a, b, c, d, in[ 4], S41, (4149444226)); /* 61 */
  II ( d, a, b, c, in[11], S42, (3174756917)); /* 62 */
  II ( c, d, a, b, in[ 2], S43, ( 718787259)); /* 63 */
  II ( b, c, d, a, in[ 9], S44, (3951481745)); /* 64 */

  buf[0] += a;
  buf[1] += b;
  buf[2] += c;
  buf[3] += d;
}
